CichlidFish.com - Fish That Think.

how do i determine the sex of my oscar.

I changed your poll questions and added in some more, as it is a good question as ppl see these small Oscars in a tank at 2" and want to know the sex of them RIGHT OFF.. WELL, they can not be sexed like the normal cichlids... So we will leave it like this and see what comes of it..

mel19641 wrote:how do i determine the sex of my oscar.

it is impossible to sex oscars as there is no visable differences

it is 99.9% impossible to tell the sex of an Oscar, the only way to tell and even it is highly difficult is to look at its genitals the females are supposed to be slightly more rounded, or get a whole bunch and wait to see what pairs off.

I believe you have to do what is called venting: the fish has to be turned upside down to check the 2 holes, the male has the same size holes, female different size.

I would say fins would have a minimal difference, but probably not enough to tell unless you have properly sexed fish for many years.

Size and color have so many factors, including tank conditions and each fish's resistance to non-perfection of water quality, food contents and amount each fish eats, size of tank, any diseases or damage one has and another hasn't, etc.

Venting or watching one lay eggs and they become fertilized would be the only sure way to know.

found this site for you:

http://www.geocities.com/cichlidiot_2000/sex.html

Hope you like it.

I have read something before that the slope of the forehead is different.  Don't remember which way for sure, but I think the female has a more smooth, even slope from nose to dorsal fin, the male with have a spot where it aggressively raises up a bit then continues to the dorsal fin I would guess somewhere around/just behind the eye area (compared to the female, but not major in any means).  I couldn't find that article, but everything I have read before said it was very difficult even to experienced people without venting.

Thanks Kenshin_Himura, the website you quoted is my own Glad to see people are still visiting the old Oscar Study Page!!

The reason why Oscars cannot be sexed by the slope of the forehead is because their physical appearance, unlike many other species, is many times determined by their disease and "abuse" history. To use a trite phrase, they scar easily, or their features reflect their experience. Additionally, I think many aquarists seem to think that Oscars will follow the Central American Cichlid trait of the males developing the huge forehead humps if left alone. If males do this, it's very subtle, almost (if not entirely) unnoticeable. The only true visual method to sex Os is by venting, unless you are 1.)very experienced and 2.) you know the history of the Oscars you are comparing. --Mark